Acceptance and widespread use of the CO2 laser in endoscopic surgery still awaits a safe, reliable and inexpensive fiber optic system to permit flexible delivery of thermalizing energy collinear with visualization of the event. Because of the need for this device in medicine and also because its fabrication and related research and development are suitable for a small high technology firm, commercialization is very promising. Unsolicited offers to negotiate a Phase III research agreement on this topic have been made by large health related companies. Based on favorable results and a demonstration of feasibility in Phase I, the proposed approach will investigate silver halide for surgical fiber optic fabrication in more detail. In addition to its high theoretical transmissivity, the material is non-toxic, non-hygroscopic, flexible, and workable at moderate temperatures. A number of novel fabrication refinements will be employed to reduce, below 1 dB/M, fiber transmission losses shown to be due primarily to scattering centers incurred in fabrication. Prior difficulties in providing necessary cladding and end windows will be innovatively addressed to make effective, expendible prototype fibers for evaluation by surgical teams.